The present invention relates to battery power gauging of a portable device, and more particularly, to a method for evaluating a remaining electric charge of a battery, and to an associated single chip system.
As portable devices on the market increase in number and develop prosperously and diversely, battery power gauging has been an essential issue. According to a related art method, simply measuring an output voltage of a battery is widely applied to various kinds of portable devices in order to perform battery power gauging. This related art method indeed saves costs since it suggests simply measuring the output voltage of the battery. However, low accuracy is certainly introduced, causing great inconvenience to the users of portable devices implemented according to the related art method.
In order to solve this problem, another related art method is proposed to use a high-cost battery having a specific circuit embedded therein. In addition, due to great differences between the high-cost battery and a conventional battery, many corresponding costs of the portable devices (such as design, material and labor costs) are also increased accordingly. Thus, those who implement portable devices according to this related art method will suffer from a high overall cost due to the high-cost battery. As a result, when a portable device requiring the high-cost battery to be an essential accessory thereof is launched on the market, the price of the portable device is surely unpleasant to many end users. Therefore, no matter how useful or powerful the portable device is, it can only serve a low percentage of potential end users since the sticker shock scares away other users.
Another related art method is further proposed to implement the specific circuit mentioned above to be a battery gauge integrated circuit (IC) 20 as illustrated in FIG. 1. Please note that the battery gauge IC 20 is coupled to a single cell Li-ion battery pack 10 through a plurality of terminals PACK+, T and PACK−, and is further coupled to a system 30 implemented with at least one IC, where a resistor Rsense is a high accuracy resistor for sensing an output current of the single cell Li-ion battery pack 10.
Implementing the architecture shown in FIG. 1, according to this related art method, typically requires two additional ICs, resulting in additional costs of implementing a portable device comprising the battery gauge IC 20. As shown in FIG. 1, at least four ICs are typically required in total, such as the battery gauge IC 20, the system 30, an Electrically Erasable Programmable Read Only Memory (EEPROM) 40 utilized by the battery gauge IC 20, and an external memory 50 utilized by the system 30. As the cost of the battery gauge IC 20 is still considered high to most system manufactures, the price of the portable device comprising the battery gauge IC 20 shall be high to end users. Similarly, no matter how useful or powerful the portable device is, it can only serve a low percentage of potential end users since the sticker price will scare away the potential buyers.
According to another related art method, it is suggested to implement a battery gauge IC with an EEPROM embedded therein, in order to decrease the total number of ICs. However, the cost of the battery gauge IC implemented according to this related art method is still high to most system manufactures.
As mentioned, related art problems such as the low accuracy of battery power gauging implemented by simply measuring the output voltage of the battery and the corresponding inconvenience to users due to the low accuracy still exist. In addition, neither the high-cost battery nor the battery gauge IC 20 and the like have really solved the related art problems mentioned above. Thus, a novel method and associated system are therefore required for solving the related art problems.